Automatic stoker for circular grates



Oct. 27, 1931. H. GLEICHMANN ET AL 1,829,275

AUTOMATIC STOKER FOR CIRCULAR GRATES Filed Sept. 20, 1929 k 23 20 A6727/4 7 W 204 W 2 H 5 ram 22 3 a X M a a 7 a A? ing mechanism,

Patented Oct. 27, 1931 UNITED STATES PATENT OFFICE HANS GLEICHMANN, 0FFALKENEAIN, NEAR SPAN'DAU, AND WILHELM GUMZ, OF IBEBLIN-OEARLOTTENBURG,GERMANY, ASSIGNOBS T0 SIEMENS-SGHUCKEBTW'EBKE, GESELLSGEAI'T MIT.IBESCHRANKTER HAFTUNG, IN 'LIQUIDATION, 0F BERLIN- SIEMRTSSTADT,GERMANY, A'CORPORATION OF GERMANY AUTOMATIC STOKER FOR CIRCULAR GRAmOriginal application filed October 7 1926, Serial No. 140,188. Dividedand this application filed September 20, 1929, Serial No. 893,968, andin Germany May 3, 1926.

Our invention relates to automatic stokers for circular grates as ageemployed for cylindrical vertical combustion chambers for boilers or thelike, and as are illustrated in our copending'application for steamgenerators, Serial No. 140,188, filed October 7, 1926, of which thepresent application is a division. The specific features covered in thepresent application refer to the type of stoker illustrated in originalFigs. '6 and 7 of the aforementioned parent application.

It is known ,in the prior art tosupply solid or lump fuel to grates bymeans of reciprocating pistons which operate at the bottom of a fuelsupply chute in such manner that at each stroke of the piston or pistonsthe fuel which has run to the bottom of the chute is pushed forward ontothe grate. The present invention in particular relates to theapplication of this idea in an improved form to circular grates in whichthe fuel is supplied by a number ofpistons from the grate peripherytowards the center, in such manner that each piston pushes the fuelwhich'is supplied to it into an individual retort which is open at thetop and in which the fuel slides on the grate towards thecenter. By thisarrangement the uniform travel of the fuel during combustion is insured.

Our invention is illustrated in the accompanying drawings in which Fig.1 represents in longitudinal vertical section one half of the grate andthe operat- Fig. -2 represents a plan view thereof, partly diagrammaticthe combustion cham- -her wall being shown in horizontal section on theline 22 Fig. 1, and

Fig. 3 represents an enlarged fragmentary detail of the gear drive 10,10 for the cam carriage 22, in plan view as shown in Fig. 2.

Referring to the drawings 1 represents the lower portion of thecombustion chamber at the bottom of whicha circular grate 2 is arrangedwhich consists' of a plurality of ra-- dially extending ridges 2 whichextend from the periphery to within a suitable distance from the gratecenter; Between these ridges are thus formed open retorts 3 into whichthe fuel pushed bymeans of pistons 5, one

ring is provided withteeth whic piston being arranged in radialalignment with each retort as shown in the drawings. Above each piston asupply chute 4 is arranged through which the fuel is supplied in frontof the piston when the latter is withdrawn, and in the position shown inFig. 1 in full lines. When the piston is moved to the left as shown inFig. 1 into the dottedposition by mechanism to be described presently,the fuel is pushed into retort 3 between the ridges 2 in whichit isforced during the succeeding piston strokes gradually towards the gratecenter while it is consumed, so that the ash from all retorts drops intothe ash pit 15. At the bottom of this ash pit is arranged a conicalgrinder 16 operated by a motor 18 by which the ash is granulated,whereafter it is delivered onto discharge chute 17 The combustion airrequired from below the fuel bed is supplied through a circular main airduct 19 from which the air passes through individual discharge openings19 into an air chamber 14 arranged underneath their sides which form theretorts, so that the air from chamber 14 can pass into themterior ofthese ridges and, out through the openings 21 into the fuel.

The individual pistons for the retorts are operated in the followingmanner. 1

Outside of pistons 5 is provided a rotatable ring 22 which travels onrollers 11 as shown inFig. 1 and which is laterally guided by guiderollers12. The outer periplhery of this mesh with a driving pinion 10driven by means of the worm gear'lO through a motor 9, as shown indetail in Fig. 3. On ring 22 is provided a sinusoidally shaped cam rail8 whose form is indicated in Fig. 2 partly in full lines and partly indash and dot lines. Each piston.

is provided with a piston rod 23 which extendsradially across cam rail8, and is provided with two vertical guide rollers 20 which are disposedon each side of cam track 8.

Each piston rod 23 is supported at its outer endin a slide bearing 7 Itwill th is be understood that when the cam rail 8 1s rotated around thegrate by motor 9, each piston 'will be reciprocated in radial direction.The pitch of cam rail 8 is chosen so that when for instance in Fig. 2piston rod I has withdrawn its the next adjacent piston rod II hasthrust its piston into the innermost position. Thus, speaking of theentire circular group of pistons arranged around the grate, adjacentpistons alternately move inward and out- Ward so that the fuel supplyonto the grate as a whole is practically uniform and continuous. Bysuitably controlling the speed or the like,

of rotation of cam 8 it is very easy to exactly regulate the fuel supplyper unit of time.

We claim: 1. An automatic stoker device for furnaces or the like,comprising a circular grate divided radially into a plurality ofretorts,

means for feeding fuel to said retorts in-' cluding a radially disposedpiston for each' retort adaptedto push the fuel, supplied, in

the direction of the grate center, a circular cam rail rotatablydisposed around said piston 5 into its outermost position,

mon operating device adapted to simultaneously reciprocatesaid pistons;1

5. An automatic stoker device for.'furnaces or the like, comprising acircular grate divided radially into a plurality of retorts, means forfeeding fuel to said retorts including a radially disposed piston foreach grate, and suitable connection between said cam rail and saidpistons to reciprocate the latter when said cam rail is rotated aroundsaid grate.

2. An automatic stoker device for furnaces comprising a circular gratedivided radially-into a plurality of retorts,

means for feeding fuel to said retorts in-'' cluding a radially disposedpiston for each retort adapted to push the fuel, supplied, in

the direction of the grate center, an annular cam carriage rotatablydisposed around said grate, a sinusoidally curved cam rail mounted onsaid carriage and cam rollers connected to each of said pistons andengaging both sides of said rail and adapted to reciprocate saidpistonswhen said carriage is rotated,

vertical guide rollers disposed along the side of said carriage forrotatably guiding it, and means for rotating said carriage.

3. An automatic stoker device for furnaces or the like, comprising acircular grate and a plurality of radially movable pistons disposedaround the grate periphery and adapted to feed fuel onto said grate, anannular cam carriage disposed to rotate around said grate and having asinusoidally curved camv rail mounted'upon said carriage and cam rollersconnected to each of said pistons and engaging both sides of said railand adapted to reciprocate said pistons when said carriage is rotated,vertical guide rollers disposed along the side of said carriage, for

rotatably guiding it, and means for rotating said carriage. I

4. An automatic stoker devlce for furnaces or the llke, comprising acircular grate divided radially into a plurality of retorts,

means for feeding fuel to said retorts in cluding a radially disposedpiston for each retort adapted to push the fuel, sup lied, in

the direction of the grate center, an a com-

